Soon Health Canada will unveil its new Canada Food Guide; the last version was released 10 years ago and the previous, 15 years earlier. The food we eat is a very important, if not the most important, factor affecting our health. The new guide will, therefore, have a profound, long-term impact on Canadians, so it is critical that we get it right this time.

Canadians might be surprised to learn that the high-carbohydrate, low-fat diet, recommended by Heath Canada for the last 50 years has never been conclusively validated by science and is, ironically, likely responsible for much of the chronic disease that afflicts our aging population. In a sense, the past 50 years of nutrition science have been a grand experiment on hundreds of millions of North Americans who have been advised to eat a high-carbohydrate, low-fat diet. The results are clear: more than 50 per cent of us are now overweight or obese, insulin resistant, and inflamed; the rates of diabetes are skyrocketing; and cancer and cardiovascular disease are the most common killers. Roughly 70 per cent of chronic disease is caused, directly or indirectly, by what I call the axis of illness: inflammation, obesity, and insulin resistance — three factors that work synergistically over time to worsen health outcomes.

As a health educator and nutrition researcher, I have been investigating the health benefits of low-carbohydrate, high-fat (ketogenic) diets in preventing and treating chronic disease. There is now compelling evidence that most Canadians can significantly improve their health by adopting this lifestyle. As robust research indicates, reducing dietary carbohydrate reverses the harmful effects of high-carbohydrate diets, often quite quickly, and reduces the incidence and severity of chronic disease.

It works like this: carbohydrates are made of simple sugar, mostly glucose. The consumption of carbohydrates (sugars and starches) causes an increase in blood glucose (commonly called blood sugar), which, in turn, causes our pancreas to secrete insulin, a powerful hormone that allows our cells to utilize the glucose.

A diet chronically high in carbohydrate, causes chronically high levels of insulin in the blood. High insulin makes our body store glucose as fat, rather than use it for quick energy. The result: obesity. The type of fat produced in this process, visceral fat, is the worst kind for your health because it promotes systemic inflammation. But the damage doesn’t end there. Chronically high levels of insulin also cause cells to become less responsive to its hormonal signal to uptake glucose. In a vicious circle, the pancreas has to work even harder to release more insulin, eventually leading to a condition called insulin resistance (pre-diabetes) and, untreated, to full-blown Type II diabetes.

Over time — decades — we get fat, inflamed, and insulin resistant, three conditions that all make each other worse. This axis of illness is largely responsible for chronic diseases such as cardiovascular disease, diabetes, Alzheimer’s disease, and cancer. Cardiovascular disease is caused, not by fat in our diet, but by inflammation in our blood vessels. Type II diabetes is aggravated by both obesity and inflammation. Alzheimer’s disease, an inflammatory disease caused by an insulin resistant brain, is sometimes called Type III diabetes. The majority of cancers are dependent on glucose, exclusively, as a fuel: something known as the Warburg effect. Cancer cells’ rate of glucose uptake is about 200 times that of normal cells, so high glucose means ample fuel for tumor growth. Furthermore, inflammation and insulin also promote tumor growth, so a high-carbohydrate diet provides the fuel and fertilizer that creates an optimal environment for cancer progression.

Fortunately, there is good news. Greatly restricting dietary carbohydrate — a ketogenic diet — reduces blood glucose and insulin secretion, which causes our cells to burn fat, rather than store it, so our cells don’t become insulin resistant. We don’t get fat, we don’t get inflamed, and our risk of chronic disease is profoundly reduced. A 2017 low-carbohydrate diet study conducted at Indiana University and published in the journal JMIR Diabetes, involving 262 adults with Type II diabetes, found that 87 per cent of the subjects were able to reduce or eliminate their need for medication to manage their disease. And this happened within a matter of weeks, sometimes even days.

Here are some important facts from science. First, there are no essential carbohydrates. Our livers can produce all the glucose we need from fat and protein in the diet. There is no minimum amount that you must consume for good health. There are good carbohydrates — soluble and insoluble fibres — which have little impact on blood sugar or insulin. These are found in a range of non-starchy vegetables.

Second, fats — even saturated fats — are essential and are good for you. Avoiding fats means avoiding important nutrients. Saturated fats are fine, so long as they are not consumed with sugars and starches. Meats, even fatty meats, in moderation, are healthy foods and should not be avoided.

Third, sugar is not a benign source of calories. The fructose in sugar must be metabolized by the liver. When this happens it promotes fat formation, insulin resistance, inflammation, and impairs brain function. Sugar has the same effect whether it is “added” or not, or comes from fruit, cane, beets, maple trees, or honey: it all has the same negative consequences.

You might question why our government doesn’t heed this recent, robust nutrition science and embrace it in our public policy and nutrition guidelines, or why current dietary recommendations weren’t developed from well-controlled nutritional studies. Unfortunately, since this kind of research is very challenging and expensive, the current recommendations have been derived mainly from epidemiological or correlational studies. It is well understood that this kind of research produces conclusions that are, well … inconclusive and fraught with potential error. Most nutrition researchers and dieticians were educated at a time when low-fat, high-carbohydrate diets were thought to be healthy. They are heavily vested in this obsolete model and are reluctant to accept a new, scientifically validated model contrary to their beliefs. But this is what good science demands: the rejection of an existing model in the face of new, compelling evidence.

In Canada, there are presently more than 2,600 physicians and allied health professionals who are using ketogenic diets to reverse disease. We have collectively appealed to the federal health minister to recognize recent compelling evidence resulting from recent science (see changethefoodguide.ca). This includes 12 evidence-based conclusions including: that the presently recommended high-carbohydrate, low-fat diet is not, and has never been, well supported by science; that a high-fat, low-carbohydrate diet is an effective, drug-free intervention for many chronic diseases; that we must severely reduce the amount of sugar in our diet; that saturated fat is healthy; and, perhaps most important, that the new Canada Food Guide should be based on robust, scientific evidence, uninfluenced by the food industry or biased self-interest, thinly veiled as expert opinion.

Our population is aging and the burden of age-related, chronic disease is growing rapidly, which is why Health Canada must provide leadership as a trusted source of evidence-based nutritional recommendations. Canadians afford to wait another 10 years for them to get it right.

• Dr. David Harper is an associate professor of kinesiology at the University of the Fraser Valley, a visiting scientist at the B.C. Cancer Research Centre, and a member of the scientific advisory board of the Institute for Personalized Therapeutic Nutrition.

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